Tungsten sputtering target and method of manufacturing the target

ABSTRACT

The tungsten sputtering target of the present invention is characterized in that a half band width of a peak corresponding to a crystal plane ( 110 ) of the target is 0.35 or less when a surface of the target to be sputtered is analyzed by X-ray diffraction. Further, the method of manufacturing the tungsten sputtering target of the present invention is characterized by comprising the steps of: pressing a high purity tungsten powder to form a pressed compact; sintering the pressed compact to form a sintered body; working the sintered body to obtain a shape of a target; subjecting the target to a grinding work of at least one of rotary grinding and polishing; and subjecting the target to a finishing work of at least one of etching and reverse sputtering. According to the above structure, there can be provided a tungsten sputtering target and method of manufacturing the target capable of improving the in-plain uniformity in thickness of the W thin film formed on a substrate, and capable of effectively reducing the generation of the particles.

TECHNICAL FIELD

The present invention relates to a tungsten (W) sputtering target and amethod of manufacturing the same.

BACKGROUND ART

In electronic parts represented by semiconductor element and liquidcrystal display element or the like, a high purity metal of tungsten(W), molybdenum (Mo), tantalum (Ta), titanium (Ti), zirconium (Zr) andcobalt (Co) or the like and silicide compounds of these metals have beenused as a material for constituting electrodes such as a gate electrodeor the like and wiring material.

In recent years, those electronic parts have been rapidly advanced. Inparticular, in technical field of the semiconductor element representedby DRAM (Dynamic Random Access Memory), logic LSI, flash memory or thelike, demand for high-integration, high-reliability, highly functionalperformance, high speed processing has been increased, so that anaccuracy or precision in finely working technology required to form theelectrodes or wirings has been further emphasized.

Further, in order to meet the above demand, it is essential to reduce aresistance of the material for forming the electrode or the wiring.

Conventionally, as the material for forming the electrodes or thewirings used in LSI, for example, silicide compounds represented byMoSi_(x) or WSi_(x) or the like have been widely used. However, in thesedays, there have been eagerly reviewed materials having a lowerelectrical resistance. Among such the materials, tungsten (W) has a lowelectrical resistance and is also excellent in heat resistance, so thatW has attracted engineer's attention as a future material forconstituting the electrodes and wirings.

The electrodes and wirings composed of W can be obtained in such amanner that W thin film is formed on a substrate and then the thin filmis worked to form a predetermined wiring pattern by an etching treatmentor the like. As a representative film forming method, sputtering methodand CVD (chemical vapor deposition) method have been widely adopted.

Conventionally, the sputtering method has been mainly used as the methodof forming the electrodes and wirings. In the sputtering method, Wsputtering target is subjected to a sputtering operation in a vacuumchamber by utilizing noble gas represented by argon (Ar) or krypton(Kr), whereby the W films are formed.

As for the W film represented by a blanket W, the W film can be alsoformed by a technology using CVD method. However, the sputtering methodhas great advantages such that a film forming speed is more rapid, aplasma-damage against a priming film is small, and a handling operationis easy in comparison with CVD method. Therefore, there is a highpossibility that the sputtering method will be mainly adopted as afuture method of forming the electrodes.

By the way, till the present status, a size of Si wafer used in LSI hasbeen shifted from 6-inches to 8-inches, and now, Si wafer having a sizeof 8-inches has been mainly used. However, it is estimated that the sizeof the Si wafer will be further scaled up to 12-inches (diameter of 300mm) in the near future. Although the size of the sputtering target isdifferent depending on types of sputtering devices, the size of thesputtering target corresponding to 8-inch sized Si wafer is generally300 mm in diameter. Further, a target size of 400 mm or more in diametermay be required for a wafer of 12-inches class.

As a first problem to be posed by the scale up of the wafer size, anin-plain uniformity in thickness of the thin film formed from a largesized target is lowered. In this connection, “in-plain uniformity”rmeans a uniformity or homogeneity of an entire thin film formed on oneplain surface of a wafer having a predetermined diameter. Particularly,in case of the electrode used in LSI, a specific resistance of theelectrode is greatly fluctuated depending on a difference in thicknessof the film constituting the electrode. As a result, the fluctuation hasmuch effect on characteristics of a transistor. In other words, when theuniformity in thickness of the thin film formed as the electrode is notgood, a production yield of LSI is lowered and thus exerting a greatdamage for the LSI manufacturer.

The in-plain uniformity in thickness of the thin film formed by thesputtering operation is greatly influenced by the sputtering conditionsi.e., various parameters such as an input power level, gas pressure,distance between the target and a substrate (wafer) or the like.However, even if these parameters are strictly controlled, the in-plainuniformity in thickness of the thin film, which is attainable by using aconventional sputtering device offered commercially, is limited to about3%.

As another serious problem, there has been posed a problem thatparticles (dusts) are liable to generate from the target during thesputtering operation. That is, when the particles generated at the filmforming operation or generated after the film formation are mixed intothe thin film or remain on the thin film, the following problems arise.Namely, a resistance value of the thin film is changed at a portionwhere the particle is mixed or remains on the thin film thereby to causea problem of disconnection or short-circuit when the thin film isassembled as a product. Further, the portion where the particle remainsis formed to be a convex shape, and the convex portion is more severelyshaved than other portions at a subsequent process such as CMP (chemicalmechanical polishing) process or the like, whereby a particle drops offtherefrom. As a result, a concave portion having a similar shape of theparticle is formed, and a resistance value of the concave portion isalso changed thereby to cause the problem of the disconnection or theshort-circuit when the thin film is assembled as a product. Furthermore,the concave portion is not properly etched under normal etchingconditions in comparison with other normal portions, so that there isposed a problem that an accurate patterning of the circuit cannot beperformed.

There are several mechanisms of generating the particles. One case isthat an abnormal discharge is occurred at a surface of the sputteringtarget during the sputtering operation, a molten particle generated bythe abnormal discharge is scattered and adhered to the wafer. Anothercase is that a film re-adhered to an outer peripheral portion of thesputtering target is peeled off therefrom due to heat cycle of thesputtering operation, and the peeled film segments are again adhered tothe wafer.

As described above, when the uniformity in thickness of the thin filmformed as the electrode is not good or the amount of the generatedparticles is large, the production yield of LSI is lowered and LSI makersuffers a great damage.

As to also W film, the same problems of the particle generation and thein-plain uniformity in thickness of the thin film formed from the abovesputtering target are applied. As the sputtering target for forming theW film, the following W sputtering targets are well known. For example,Japanese Patent Application (Laid-Open) No. HEI-5-93267 discloses asputtering target having a carbon content of 50 ppm or less, oxygencontent of 30 ppm or less, a relative density of 97% or more, whereincrystal grains have a shape collapsed in a predetermined direction.

Japanese Patent Application (Laid-Open) No. HEI-5-222525 discloses amethod of manufacturing a sputtering target comprising the steps of:pressing W powder to form a molded body having a relative density of 60%or more, heating the molded body to a temperature of 1400° C. or higherin an atmosphere containing hydrogen gas to form a sintered body havinga relative density of 90% or more, and hot-working the sintered body toobtain a relative density of 99% or more.

Japanese Patent Application (Laid-Open) No. HEI-7-76771 discloses asputtering target having a relative density of 99.5% or more and anaverage crystal grain size of more than 10 μm up to 200 μm.

However, even if the film forming operation is performed using the aboveconventional W sputtering targets under predetermined sputteringconditions, an attainable limit of the in-plain uniformity in thicknessof the W thin film was about 3% and the particle reduction was notsatisfactory indeed.

In recent years, in accordance with an increase of the technical demandsfor high integration, high processing speed, high reliability requiredfor LSI, it has been essentially required for the material for formingthe electrode and wiring to lower the resistance. In view of thisdemand, the material for forming the electrode has been changed fromsilicide to a high purity metal. Since the attainable limit of thein-plain uniformity in thickness of the W thin film formed by using theconventionally well-known sputtering target is about 3%, when the sizeof wafer is further increased, there must be shown a tendency that thein-plain uniformity in thickness of the thin film is greatlydeteriorated.

In addition, it is also an important issue to reduce the particlesgenerated from the sputtering target. In particular, as to the size ofthe particles generated by the abnormal discharge, the particles havinga size of 1 μm or more are in the majority, so that the reduction of theparticles having a size of 1 μm or more have been strongly demanded inthese days.

If these phenomena are not eliminated, the production in themass-producing line of LSI is greatly lowered and there may be arisengreater loss capability.

The present invention had been achieved to solve the aforementionedproblems, and an object of the present invention is to provide a Wsputtering target and method of manufacturing the target capable ofimproving the in-plain uniformity in thickness of the W thin film formedon, for example, a large-sized substrate having a diameter of 8-inchesor more.

DISCLOSURE OF THE INVENTION

In order to solve the aforementioned problems, the inventors of thisinvention had variously reviewed about crystal orientations and crystalplanes of a surface of W sputtering target, and uniformity in thicknessof film formed by using the target. As a result, the inventors had foundthat the uniformity in thickness of W thin film formed on Si waferhaving a diameter of 8-inches or more could be reduced to be 1% orlower, to which the conventional targets had never attained.

The present invention had achieved on the basis of the aforementionedfindings. That is, a tungsten sputtering target according to a firstinvention is characterized in that a half band width of a peakcorresponding to a crystal plane (110) of the target is 0.35 or lesswhen a surface of the target to be sputtered is analyzed by X-raydiffraction. In the present invention, when the half band width of thepeak corresponding to the crystal plane (110) of the surface of thetarget to be sputtered is set to 0.35 or less, it becomes possible toimprove the in-plain uniformity in thickness of W thin film formed byusing the sputtering target.

In the first invention, in addition to the half band width of thespecified crystal plane (110), it is preferable that a dispersion of thehalf band width is 30% or less. By reducing this dispersion to 30% orless, it becomes possible to further improve the in-plain uniformity inthickness of W thin film thus formed.

Further, the inventors of the present invention had also obtained thefollowing findings. Namely, when a specified crystal orientation ratioat the surface of the target is controlled, the uniformity in thicknessof W thin film formed on a large-scaled Si wafer, for example, having adiameter of 8-inches or more could be improved to be an excellent levelto which the conventional targets had never attained, and the generationof the particles could be reduced.

In a case where the sputtering operation is performed by using theconventional high purity W sputtering target, the uniformity inthickness had reached a critical limit of about 3% in regardless of thefilm forming conditions. In a case where the size of wafer is furtherincreased, for example, to 12-inches wafer, the uniformity in thicknessis disadvantageously increased to about 5%. The inventors of thisinvention had found that a releasing angle distribution of neutralgrains and ions scattered from the W sputtering target was an importantfactor to further improve the uniformity in thickness, so that theinventors of this invention had investigated about the releasing angledistribution in various technical viewpoints. As a result, the inventorsof this invention had found that a crystal orientation ratio (110)/(200)obtained from peak intensities of crystal planes (110) and (200) of asurface of the target analyzed by X-ray diffraction effectively affecton the uniformity in thickness.

From the above findings, the tungsten sputtering target according to asecond invention is characterized in that a crystal orientation ratio(110)/(200) is 0.1-6.5 when a peak intensity of a crystal plane (110)and a peak intensity of a crystal plane (200) of a surface of the targetto be sputtered are analyzed by X-ray diffraction.

Namely, when the above second invention is adopted, it becomes possibleto improve the in-plain uniformity in thickness of the W thin filmformed by using the W sputtering target.

Furthermore, when a plastic forming is performed to manufacture the Wsputtering target, a slip is liable to occur due to the plastic forming.As to the slip, a slip plane and a slip direction are specified for eachof the crystal structures. The phenomenon of the slipcrystallographically occurs at a crystal plane where atoms are mostdensely existing or at a crystal plane close to the most dense crystalplane. When the slip occurs, the crystal plane is formed withfault-shaped step, so called, slip plane or slip belt. When thesputtering operation is advanced, this slip plane (slip belt) is formedwith fault-shaped concavo-convex. When the sputtering operation iscontinued, the ups and downs of this concavo-convex are furtherincreased. The inventors of this invention had found the followingfindings. That is, when the ups and downs of this concavo-convex arefurther increased, the electrical charge is concentrated at the convexportion of this concavo-convex, thereby to cause the abnormal discharge.As the results of the reviewing the slip, the inventors of thisinvention had found that a crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} obtained when peak intensities ofcrystal planes (110), (200), (211), (220) and (310) of a surface of thetarget to be sputtered are analyzed by X-ray diffraction exerts aneffective influence on the abnormal discharge and the particles.

On the basis of the above findings, a tungsten sputtering target of athird invention is characterized in that a crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} is 0.17 or less when peakintensities of a crystal plane (110), a crystal plane (200), a crystalplane (211), a crystal plane (220) and a crystal plane (310) of asurface of the target to be sputtered are analyzed by X-ray diffraction.

Namely, when the above third invention is adopted, it becomes possibleto reduce the particles to be mixed in the W film formed by using the Wsputtering target.

Further, a tungsten sputtering target according to a fourth invention ischaracterized in that a crystal orientation ratio (110)/(200) is 0.1-6.5and a crystal orientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} is0.17 when peak intensities of a crystal plane (110), a crystal plane(200), a crystal plane (211), a crystal plane (220) and a crystal plane(310) of a surface of the target to be sputtered are analyzed by X-raydiffraction.

Namely, when the above fourth invention is adopted, it becomes possibleto improve the in-plain uniformity in thickness of the W film and toreduce the particles to be mixed in the W film formed by using the Wsputtering target.

Furthermore, a method of manufacturing the high purity tungstensputtering target according to another aspect of the present inventionis characterized by comprising the steps of: pressing a high puritytungsten powder to form a pressed compact; sintering the pressed compactto form a sintered body; working the sintered body to obtain a shape ofa target; subjecting the target to a grinding work of at least one ofrotary grinding and polishing; and subjecting the target to a finishingwork of at least one of etching and reverse sputtering.

By employing the aforementioned method of manufacturing the target, itbecomes possible to manufacture the sputtering target having apredetermined half band width or less specified by the presentinvention.

In the method of manufacturing the tungsten sputtering target accordingto the present invention, it is preferable that the method furthercomprises an intermediate sintering step for maintaining the pressedcompact at temperature of 1450-1700° C. for one hour or longer after thepressed compact is heated at a heating-up rate of 2-5° C./min on the wayto a maximum sintering temperature when the high purity tungsten powderis pressed and sintered by hot pressing method.

By employing the aforementioned intermediate sintering step, it becomespossible to manufacture the sputtering target having a predetermineddispersion of the half band width or less specified by the presentinvention.

The configurations and structures of each of the inventions will bedescribed hereunder in detail.

BRIEF DESCRIPTION OF THE DRAWING

In the accompanying drawing:

FIG. 1 is a schematic plan view showing sampling points at which testpieces are sampled for measuring a half band width and dispersion of thehalf band widths of the target according to the present invention

BEST MODE FOR EMBODYING THE INVENTION

Hereinafter, embodiments for embodying the present invention will bedescribed.

A tungsten (W) sputtering target according to the present invention ischaracterized in that a half band width of a peak corresponding to acrystal plane (110) of the target is 0.35 or less when a surface of thetarget to be sputtered is analyzed by X-ray diffraction.

When the sputtering target constructed as above is used, it becomespossible to improve the in-plain uniformity in thickness of the W film.That is, for example, when a W film is formed on an Si wafer having adiameter of 8-inches or more in accordance with a sputtering methodusing a tungsten sputtering target, it becomes possible to improve theuniformity in thickness of the W thin film thereby to control thedispersion of the specific resistance distribution in a plain of thewafer.

In a case where the sputtering operation is performed by using theconventional high purity W sputtering target, the uniformity inthickness had reached a critical limit of about 3% in regardless of thefilm forming conditions. In a case where the size of wafer is furtherincreased, for example, to 12-inches wafer, the uniformity in thicknessis disadvantageously increased to about 5%.

The inventors of this invention had found that a releasing angledistribution of neutral grains and ions scattered from the W sputteringtarget was an important factor to further improve the uniformity inthickness, so that the inventors of this invention had investigatedabout this point from various technical viewpoints. As a result, theinventors of this invention had found that if a half band width of apeak of crystal plane (110) of a surface of the target analyzed by X-raydiffraction is 0.35 or less, it effectively affects on the uniformity inthickness of the thin film.

In general, as a crystal plane of a W sintered body having abody-centered cubic (BCC) structure, there are several kinds of crystalplanes such as crystal plane (110), crystal plane (200), crystal plane(211), crystal plane (220), crystal plane (310) or the like. Among theabove crystal planes, the crystal plane (110) is the most closestpacking plane of the BCC structure, and a gap is hardly formed betweenthe crystal lattices. Therefore, a noble gas such as Ar atom is hardlyto be taken into the crystal lattice during the sputtering operation, sothat a sputtering rate is considered to be the highest at the crystalplane (110). This estimation can be also understood from a fact that thecrystal plane (110) shows a main peak value in JCPDS (Joint Committee onPowder Diffraction Standards) card.

Normally, the surface of the sputtering target is finished andcontrolled the surface condition by subjecting the surface toamechanical grinding such as lathe work, rotary grinding, polishing orthe like. However, the surface of the sputtering target is formed withmany internal distortions due to the mechanical working, and the targetsare usually used in this condition. As described hereinbefore, since thecrystal plane (110) has the highest sputtering rate, the smallerinternal distortion is included in the crystal plane (110), the crystalplane (110) exhibits the more stable releasing angle distribution. Inthe present invention, the internal distortion contained in the crystalplane (110) is expressed by the half band width.

In general case of the magnetron sputtering method,the temperature ofthe surface of the sputtering target will attain 400° C. or higher dueto the generation of plasma. In this case, when the internal distortionis contained in crystal plane at surface of the target, there arise aphenomenon such that the distortion is released due to a heat affectionat the sputtering operation, and there is caused a slight difference insputtering releasing angle distribution. Therefore, when the surface ofthe target to be sputtered is analyzed by X-ray diffraction and the halfband width of a peak corresponding to a crystal plane (110) of thetarget exceeds 0.35, the releasing of the internal distortion ispromoted, so that the releasing angle distribution is drasticallychanged. Thus resulting in a bad influence on a thickness distributionof the film.

Accordingly, in order to realize a W sputtering target capable ofreducing the internal distortion and obtaining a stable releasing angledistribution, the present invention specifies the half band width of apeak corresponding to a crystal plane (110) of the target to be 0.35 orless when a surface of the target to be sputtered is analyzed by X-raydiffraction. The half band width is more preferable to be 0.3 or less,furthermore preferable to be 0.2 or less, still furthermore preferableto be 0.15 or less.

It is preferable that a dispersion of the half band width of the crystalplane (110) formed in the target surface is 30% or less.

This is because when the dispersion of the entire crystal planes (110)exceeds 30 even if the half band width is within a range specified bythis invention, as is the same phenomenon as described hereinbefore, thereleasing angle distribution is liable to cause an unevenness, so thatuniformity in thickness of the film to be formed on the wafer isdeteriorated. Accordingly, the dispersion of the half band width isspecified to 30% or less. This dispersion is preferable to be 20% orless, more preferably be 15% or less.

The tungsten sputtering target according to the second invention ischaracterized in that a crystal orientation ratio (110)/(200) is 0.1-6.5when a peak intensity of a crystal plane (110) and a peak intensity of acrystal plane (200) of a surface of the target to be sputtered areanalyzed by X-ray diffraction.

The inventors of this invention had reviewed about the in-plainuniformity in relation with the crystal plane (110) and other crystalplanes. As a result, the inventors had found that a crystal orientationratio of the crystal plane (200) exerts a great influence on thein-plain uniformity, and when a W sputtering target is prepared so thata crystal orientation ratio (110)/(200) is controlled to be a specifiedrange, i.e., 0.1 to 6.5, the in-plain uniformity of thus obtained W filmcan be improved thereby to achieve the second invention.

In general, in case of the magnetron sputtering method, a surfacecondition of the W sputtering target is hardly changed at early stage ofthe sputtering operation. However, when the sputtering operation isadvanced, only a portion formed with a strong magnetic field is greatlyconsumed while forming a specified slant angle. As a result, so called,a most eroded portion is formed.

In this case, a shape of the sputtered surface of the target is changedwhen the sputtering operation is further advanced from an initial stageof the sputtering, so that the releasing angle distribution of thesputtered grains is also greatly changed. When the crystal orientationratio is outside the above range, the influence of the change in shapeof the target surface on the releasing angle distribution of thesputtered grains has a more significant impact than that of the changein crystal orientation, so that the crystal orientation ratio(110)/(200) is specified to a range of 0.1-6.5. The preferable range ofthis crystal orientation ratio is 1-5, and more preferably be a range of2-4.

Further, when the dispersion of this crystal orientation ratio is toolarge in entire W sputtering target, an evenness in the releasing angledistribution would occur and a difference in thickness of thus formed Wfilm is enlarged, so that the dispersion of this crystal orientationratio is preferably be set to 50% or less. The more preferable range ofthis dispersion is 30% or less, and the most preferable range is 15% orless.

Next, the tungsten sputtering target according to a third invention ischaracterized in that a crystal orientation ratio(211)/{(110)+(200)+(211)+(220) +(310)} is 0.17 or less when peakintensities of a crystal plane (110), a crystal plane (200), a crystalplane (211), a crystal plane (220) and a crystal plane (310) of asurface of the target to be sputtered are analyzed by X-ray diffraction.

As described hereinbefore, when the sputtering operation is continued,this slip plane (slip belt) of the W sputtering target is formed withfault-shaped concavo-convex. The ups and downs of this concavo-convex isfurther greatened when the sputtering operation is further continued.The inventors of this invention had found the following findings. Thatis, when the ups and downs of this concavo-convex are further increased,the electrical charge is concentrated at the convex portion of thisconcavo-convex thereby to-cause the abnormal discharge. As the resultsof the reviewing the slip, the inventors of this invention had foundthat when a crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} obtained when peak intensities ofcrystal planes (110), (200), (211), (220) and (310) of a surface of thetarget to be sputtered are analyzed by X-ray diffraction is set to aspecified range, i.e., 0.17 or less, the amount of the particles to bemixed in the W film can be effectively decreased. More particularly, theamount of particles each having a diameter of 1 μm or less can besignificantly reduced.

In this regard, when the above crystal orientation ratio is excessivelylarge, the ups and downs of this concavo-convex formed at the slip planeis further greatened thereby to form a large convex portion. Then,electrical charge is concentrated to the convex portion and the abnormaldischarge is liable to occur thereby to increase the amount of theparticles. Therefore, the crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} is set to 0.17 or less. The morepreferable range of this crystal orientation ratio is 0.15 or less, andthe most preferable range is 0.1 or less.

Further, when the dispersion of this crystal orientation ratio is toolarge in entire W sputtering target, an evenness in the releasing angledistribution would occur and a difference in thickness of thus formed Wfilm is enlarged, so that the dispersion of this crystal orientationratio is preferably be set to 30% or less. The more preferable range ofthis dispersion is 15% or less, and the most preferable range is 10% orless.

In this connection, the half band width, crystal orientation ratio ofthe crystal planes and dispersion thereof specified in the presentinvention are defined as values which are measured by the followingmethods.

That is, as shown in FIG. 1, 17 pieces of test pieces are sampled fromentire sampling positions of a circular disk-shaped target. The samplingpositions consist of: a center portion (position 1) of the target; outerperipheral 8 portions (positions 2-9) located on four straight lineseach passing through the center portion and equally dividing acircumference of the target, each peripheral portion is located at adistance 90% of a radius from the center portion; and intermediate 8portions (positions 10-17) each intermediate position is located at adistance 50% of a radius from the center portion. Each test piece has asize of 15 mm×15 mm. X ray diffraction peak and crystal orientation aremeasured with respect to each of the 17 test pieces, and averaged valuesare adopted as the diffraction peak and crystal orientation. The halfband width is calculated from a diffraction peak of the respectivecrystal planes obtained by X-ray diffraction. This half band width is aratio of a peak width at half height of the peak and a peak height. Arepresenting value is obtained by averaging at least ten measured datawith respect to one measuring point. Further, the crystal orientation isgiven as a peak intensity obtained by X-ray diffraction. As an X-raydiffraction system, an X-ray diffraction apparatus manufactured byRigaku Co. Ltd. was used. The measuring conditions are as follows.

-   -   X-ray: Cu, k-α1, 50 kV, 100 mA, vertical type goniometer,    -   Divergent slit: 1 deg,    -   Dispersion slit: 0.15 mm,    -   Scanning mode: continuous    -   Scan speed: 1°/min,    -   Scan step: 0.01°, Scanning axis 2 θ/θ    -   Measuring angle: 38°˜42°

In this connection, as a chart for measuring the half band width ofX-ray diffraction, a standard chart provided with a scale length of 11mm corresponding to an X-ray intensity of 10000 cps and provided with ascale length of 23 mm corresponding to a scanning angle of 1°. In a casewhere this standard chart is not available, the half band width ismeasured on the basis of a chart modified so as to meet the standard.

Further, the dispersion of the peak intensities of the crystal planesfor entire surface of the target is a value obtained from a maximumvalue and a minimum value of the peak intensities of the respectivecrystal planes measured for 17 test pieces. The value of the dispersionis calculated on the basis of the following equation.Dispersion (%)={(maximum value−minimum value)/(maximum value+minimumvalue)}×100

In the above tungsten (W) sputtering target, it is preferable that thetungsten sputtering target has a relative density of 99% or more.

When the relative density of the target is excessively low, the amountof particle generation will disadvantageously increases. The preferablerelative density of the target is 99.5% or more, furthermore preferablybe 99.7% or more. The relative density of the target is a value measuredby means of Archimedes' method.

The W sputtering target of the present invention is permissible tocontain a small amount of impurity as far as the impurity content issimilar to that of a sputtering target composed of a normal metalmaterial having a high purity. However, when the impurity amount isexcessively large, there may be posed a fear that a leak current isincreased and a specific resistance is increased thereby to lower thecharacteristic of the W film.

Accordingly, it is preferable that the tungsten sputtering targetaccording to the present invention is constituted by a high purity Wmaterial in which a total amount of iron (Fe), nickel (Ni), chromium(Cr), copper (Cu), aluminum (Al), sodium (Na), potassium (K), uranium(U) and thorium (Th) as impurities contained in the material is 100 ppmor less.

In other words, it is preferable to use a high purity W material suchthat the purity value [100−(Fe+Ni+Cr+Cu+Al+Na+K+U+Th)] obtained bysubtracting the total content (mass%) of Fe, Ni, Cr, Cu, Al, Na, K, U,Th from 100% is 99.99% or more.

It is preferable that the tungsten sputtering target according to thepresent invention is used after being integrally bonded to a backingplate composed of Cu, Al or alloy thereof. As a bonding method forbonding to the backing plate, conventionally well known bonding methodssuch as diffusion bonding method or brazing method can be applied.

The tungsten sputtering target according to the present invention can bemanufactured in accordance with, for example, the following method.

For example, as a first method, there is a method using a hot pressingapparatus. At first, high purity W powder is pulverized by means of aball mill thereby to obtain a fine and high purity W powder containingless deformed particles. This high purity W powder is packed in a carbonmold die of which size is controlled to a size of the aimed target, andthen the W powder is pressed and sintered by the hot pressing apparatus.The high purity W powder containing a great amount of the deformedparticles would not be sufficiently sintered to internal portion even ifhigh pressure and temperature are applied to the molded body. Therefore,it is preferable to use a W powder containing the deformed particles aslittle as possible.

In the above pressing and sintering step, prior to attain a maximumsintering temperature, it is preferable to carry out a degassingtreatment for heating the molded body to a temperature of 1150° C.˜1450°C. for at least one hour. This treatment is for removing an adsorbedoxygen adhered to the material powder and impurity elements contained inthe material powder. A preferable environment for the degassingtreatment is vacuum (1 Pa or lower) or H₂ gas atmosphere.

After completion of the degassing treatment, the molded body is heatedand sintered at a predetermined intermediate sintering temperature whilebeing applied with a pressure of 20 MPa or higher under a vacuum of 1 Paor lower.

In this regard, prior to attain the intermediate sintering temperature,it is preferable to heat the molded body at a heating speed of 2-5°C./min and hold the molded body at the intermediate sinteringtemperature of 1450-1700° C. for one hour or longer.

By conducting the intermediate sintering step, a uniformity intemperature of a sintered body can be improved, and pores and voidsincluded in the sintered body can be also effectively removed. Further,due to this intermediate sintering step, the dispersion of the half bandwidth of the crystal plane (110) can be controlled to within a rangespecified in the present invention.

Next, after completion of the intermediate sintering step, the sinteredbody is heated to the maximum sintering temperature to conduct a finalsintering operation. The maximum sintering temperature is preferably setto 1900° C. or higher. A retention time (holding time) at the maximumsintering temperature is preferably set to 5 hours or longer.

As a cooling operation after the final sintering step, for example, itis preferable to release the pressure applied to the sintered body andthen cool the sintered body at a cooling speed of 10° C./min or more.Further, the press-sintered body may be further subjected to a hotisostatic pressing (HIP) treatment. It is preferable to set thetemperature for HIP treatment to 1400-1800° C., and set the pressure to150 MPa or higher. By conducting such HIP treatment, it becomes possibleto obtain a denser sintered body.

In this connection, when the above sintered body is subjected to a heattreatment so as to be heated to temperature of 1000-1300° C. in a vacuumor hydrogen (H₂) gas atmosphere for at least one hour, the half bandwidth becomes small and a W sputtering target having a preferable halfband width can be easily obtained, thus being preferable to conduct theheat treatment.

As another manufacturing method, after the material powder is subjectedto a cold isostatic pressing (CIP) treatment, the molded body issubjected to HIP treatment, followed by hydrogen-sintered, then theresultant sintered body may be subjected to a hot rolling or hotforging.

As still another manufacturing method, after completion of the above hotpressing (HP) or hot isostatic pressing (HIP), the sintered body may befurther subjected to the hydrogen-sintering treatment, thereafter, thehot forging and the hot rolling may be carried out to the sintered body.

As yet another manufacturing method, the target may be manufactured inaccordance with a CVD (chemical vapor deposition) method using WF₆/H₂gas or the like. The target may also be manufactured in accordance witha sputtering method, an ion plating method, a flame spray coating methodor a vacuum evaporation method.

Thus obtained target material (sintered body) is machine-worked therebyto form into a predetermined shape of a target.

Next, thus obtained target material is subjected to the followingsurface finishing treatment, so that there can be obtained a target ofwhich half band width of the crystal plane (110) of a surface to besputtered is within the range specified in this invention.

At first, in the present invention, the surface of the target to besputtered is subjected to at least one of rotary grinding and polishing.In particular, it is preferable to conduct the rotary grindingthereafter to conduct the polishing. In this case, a surface roughnessof the target is preferably set to 1 μm or less in terms of arithmeticaverage roughness (Ra).

In the present invention, after conducting the above grinding work, asurface treatment such as a wet or dry etching or a reverse sputteringmethod or the like is carried out to the sintered body. In this case,the surface roughness is preferably set to 0.5 μm or less in terms ofarithmetic average roughness (Ra). As an etching solution used for thewet-etching process, it is possible to use potassium ferricyanide (redprussiate) or the like. As an etching gas used for dry etching process,it is possible to use CF₄/O₂ mixed gas or the like.

In the present invention, by conducting the above finishing work, itbecomes possible to remove the internal distortion accumulated at thecrystal planes due to the mechanical work for the target material, andpossible to set the half band Width to within a range specified in thepresent invention.

Next, as a method of manufacturing a W sputtering target of the secondinvention in which a crystal orientation ratio (110)/(200) is specified,a method using a hot press will be explained hereunder.

At first, high purity W powder is pulverized in argon (Ar) gasatmosphere or hydrogen gas atmosphere for 24 hours or longer by means ofa ball mill thereby to obtain a fine and high purity W powder containingless deformed particles.

This high purity W powder is packed in a carbon mold die of which sizeis controlled to a size of the aimed target, and then the W powder ispressed and sintered by the hot pressing apparatus. The high purity Wpowder containing a great amount of the deformed particles would not besufficiently sintered to internal portion even if high pressure andtemperature are applied to the molded body. Therefore, it is preferableto use a W powder containing the deformed particles as little aspossible. Further, it is preferable to use a W powder having an oxygencontent of 2000 ppm or less. This is because, when the oxygen content islarge, the W powder would not be sufficiently sintered to internalportion, so that a sintered body having a predetermined density cannotbe obtained.

In the above pressing and sintering step, prior to attain a maximumsintering temperature, it is preferable to carry out a degassingtreatment for heating the molded body to a temperature of 1150° C.˜1450°C. for at least one hour. This treatment is for removing an adsorbedoxygen adhered to the material powder and impurity elements contained inthe material powder. A preferable environment for the degassingtreatment is vacuum (1 Pa or lower) or H₂ gas atmosphere.

After completion of the above degassing treatment, an intermediatesintering is performed so that the molded body is heated and sintered ata predetermined intermediate sintering temperature while being appliedwith a pressure of 20 MPa or higher under a vacuum of 1 Pa or lower.

In this step, it is preferable to repeat a depressing-pressing cycle atleast 5 times, the cycle comprising the steps of: releasinga pressurewhen the atmosphere attains to a predetermined pressure for theintermediate sintering; and again applying the pressure to the moldedbody. This pressuring-depressing-pressuring cycle makes it possible toimprove the density of the sintered body at the intermediate sinteringstep and to control a direction of the crystal orientation aimed by thepresent second invention.

In this regard, prior to attain to the intermediate sinteringtemperature, it is preferable to heat the molded body at a heating speedof 2-5° C./min and hold the molded body at the intermediate sinteringtemperature of 1450-1700° C. for one hour or longer. By conducting theintermediate sintering step, a uniformity in temperature of a sinteredbody can be improved, and pores and voids included in the sintered bodycan be also effectively removed. Further, due to this intermediatesintering step, the dispersion of the crystal orientation ratio(110)/(200) can be controlled to within a range specified in the presentinvention.

Next, after completion of the intermediate sintering step, the sinteredbody is heated to the maximum sintering temperature to conduct a finalsintering operation. The maximum sintering temperature is preferably setto 1900° C. or higher. A retention time (holding time) at the maximumsintering temperature is preferably set to 5 hours or longer.

As a cooling operation after the final sintering step, for example, itis preferable to release the pressure applied to the sintered body andthen cool the sintered body at a cooling speed of 10 ° C./min or more.Further, the press-sintered body may be further subjected to a hotisostatic pressing (HIP) treatment. It is preferable to set thetemperature for HIP treatment to 1400-1800° C., and set the pressure to150 MPa or higher. By conducting such HIP treatment, it becomes possibleto obtain a denser sintered body.

In this connection, when the above sintered body is further subjected toa hot working or a heat treatment so as to be heated to temperature of2000° C. or higher in a hydrogen (H₂) gas atmosphere, a W sputteringtarget having the dispersion of the crystal orientation ratio(110)/(200) specified in this invention can be easily obtained, thusbeing preferable to conduct the hot working or the heat treatment.

In this connection, the hot working means a hot forging or a hot rollingor the like. As the condition of the hot working, it is preferable thatthe sintered body is heated to 1000-1400° C. in hydrogen (H₂) gasatmosphere and held in this state for at least one hour, followed bybeing worked at a working ratio of 30% or less.

As another manufacturing method, after the material powder is subjectedto a cold isostatic pressing (CIP) treatment, the molded body issubjected to HIP treatment, followed by hydrogen-sintered, then theresultant sintered body may be subjected to a hot rolling or hotforging. As another manufacturing method, the HIP treatment can be alsosolely used.

As still another manufacturing method, after completion of the above hotpressing (HP) or hot isostatic pressing (HIP), the sintered body may befurther subjected to the hydrogen-sintering treatment, thereafter, thehot forging and the hot rolling may be carried out to the sintered body.

Next, as a method of manufacturing a W sputtering target of the secondinvention in which a crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} is specified, a method using a hotpress will be explained hereunder.

At first, high purity W powder is pulverized in argon (Ar) gasatmosphere or hydrogen gas atmosphere for 24 hours or longer by means ofa ball mill thereby to obtain a fine and high purity W powder containingless deformed particles.

This high purity W powder is packed in a carbon mold die of which sizeis controlled to a size of the aimed target, and then the W powder ispressed and sintered by the hot pressing apparatus. The high purity Wpowder containing a great amount of the deformed particles would not besufficiently sintered to internal portion even if high pressure andtemperature are applied to the molded body. Therefore, it is preferableto use a W powder containing the deformed particles as little aspossible. Further, it is preferable to use a W powder having an oxygencontent of 2000 ppm or less. This is because, when the oxygen content islarge, the W powder would not be sufficiently sintered to internalportion, so that a sintered body having a predetermined density cannotbe obtained.

In the above pressing and sintering step, prior to attain a maximumsintering temperature, it is preferable to carry out a degassingtreatment for heating the molded body to a temperature of 1150° C.˜1450°C. for at least one hour. This treatment is for removing an adsorbedoxygen adhered to the material powder and impurity elements contained inthe material powder. A preferable environment for the degassingtreatment is vacuum (1 Pa or lower) or H₂ gas atmosphere.

After completion of the above degassing treatment, an intermediatesintering is performed so that the molded body is heated and sintered ata predetermined intermediate sintering temperature while being appliedwith a pressure of 20 MPa or higher under a vacuum of 1 Pa or lower.This is because, when the applying pressure is excessively large, it isdifficult to obtain a W sputtering target having a high density.

In this step, it is preferable to repeat a depressing-pressing cycle atleast 5 times, the cycle comprising the steps of: releasing a pressurewhen the atmosphere attains to a predetermined pressure for theintermediate sintering; and again applying the pressure to the moldedbody. This pressuring-depressing-pressuring cycle makes it possible toimprove the density of the sintered body at the intermediate sinteringstep and to control a direction of the crystal orientation aimed by thepresent third invention.

In this regard, prior to attain to the intermediate sinteringtemperature, it is preferable to heat the molded body at a heating speedof 2-5° C./min and hold the molded body at the intermediate sinteringtemperature of 1450-1700° C. for one hour or longer.

By conducting the intermediate sintering step, a uniformity intemperature of a sintered body can be improved, and pores and voidsincluded in the sintered body can be also effectively removed.

Subsequently, after conducting the above intermediate sintering step,the temperature is once lowered to 800-1000° C. Then, a high pressure of4 MPa or higher is applied to the sintered body at a pressurizing speedof 1 MPa/min (10 ton/min) or more and heated to a maximum sinteringtemperature thereby to carry out the final sintering. In this regard,when the temperature to be once lowered is excessively low, the sinteredbody is liable to cause cracks due to the subsequent abruptpressurization. On the other hand, when the temperature to be oncelowered is excessively high, the releasing of the distortions containedin the sintered body becomes remarkable, so that it becomes impossibleto obtain the predetermined crystal orientation ratio. In this regard,the abrupt pressurization in which a high pressure is abruptly appliedto the sintered body at the stage of having advanced the sintering inthe intermediate sintering step (for example, the sintered density is95% or more) is performed for the purpose of promoting a slipping effectthereby to obtain a predetermined crystal orientation ratio.

After completion of this intermediate sintering step, the sintered bodyis heated to the maximum sintering temperature to conduct a finalsintering operation. The maximum sintering temperature is preferably setto 1900° C. or higher. A retention time (holding time) at the maximumsintering temperature is preferably set to 5 hours or longer. This isbecause, when the maximum sintering temperature is excessively loweredor the sintering time is excessively short, it is impossible to obtain asintered body having a predetermined density and the crystal orientationratio.

As a cooling operation after the final sintering step, for example, itis preferable to release the pressure applied to the sintered body andthen cool the sintered body at a cooling speed of 10° C./min or more.Further, the press-sintered body may be further subjected to a hotisostatic pressing (HIP) treatment. It is preferable to set thetemperature for HIP treatment to 1400-1800° C., and set the pressure to150 MPa or higher. By conducting such HIP treatment, it becomes possibleto obtain a denser sintered body.

Next, a tungsten (W) sputtering target according to the present fourthinvention in which a crystal orientation ratio (110)/(200) is 0.1-6.5and a crystal orientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} is0.17 or less when peak intensities of a crystal plane (110), a crystalplane (200), a crystal plane (211), a crystal plane (220) and a crystalplane (310) of a surface of the target to be sputtered are analyzed byX-ray diffraction, can be manufactured by appropriately select themanufacturing methods described above.

Next, thus obtained target material is subjected to the surfacefinishing treatment. It is preferable that the tungsten sputteringtarget of which surface is finished according to the present inventionis used after being integrally bonded to a backing plate composed of Cu,Al or alloy thereof. As a bonding method for bonding to the backingplate, conventionally well known bonding methods such as diffusionbonding method or brazing method can be applied.

It is preferable to carry out the brazing method by utilizing well knownIn type or Sn type brazing materials. In a case where the target isbonded to a backing plate composed of aluminum (Al), it is preferablethat the temperature at the diffusion bonding is set to 600° C. orlower. This is because, a melting point of Al is 660° C.

In accordance with the above manufacturing method, it becomes possibleto obtain the high purity W sputtering target of the present invention.

In this regard, the above described methods is merely one example of themethod for obtaining the W sputtering target of the present invention,and the method is not limited thereto as far as the method canmanufacture the W sputtering target of the present invention.

The W sputtering target of the present invention is used for forming theelectrodes and/or wirings of the electronic parts represented bysemiconductor element and liquid crystal display elements.

[Embodiments]

Next, concrete embodiments of the present invention will be explainedwith reference to the following Examples and Comparative Examples.

EXAMPLE 1

High purity W powders were prepared, and each of these high purity Wpowders was packed in a carbon mold die and the mold die was set into ahot pressing apparatus. Then, each of the packed W powders was heated toa temperature of 1250° C. and held for 3 hours under a vacuum atmosphereof 1 Pa or lower thereby to perform a degassing treatment.

Subsequently, an intermediate sintering was performed under theconditions shown in columns of the intermediate sintering step ofTable 1. That is, each of the degassed molded bodies was heated from thedegassing temperature to the intermediate sintering temperature atheating speed shown in Table 1 while being applied with a pressure of 30MPa under a vacuum atmosphere of 1 Pa or lower, and held at thetemperature for the holding time shown in Table 1, thereby to performthe intermediate sintering step.

After the above intermediate sintering step, the sintered body was heldat a temperature of 1900° C. for 5 hours, thereby to prepare a Wsintered body as a target material. A cooling operation after thesintering was performed by substituting Ar gas for the atmosphere, and acooling speed was 10° C./min.

Thus prepared W sintered body was then machine-worked so as to provide asize of the aimed target (diameter: 300 mm×thickness:5 mm). After thesurface of the target was subjected to a rotary grinding, a finishingwork shown in Table 1 was performed. Thus obtained sputtering target wasintegrally bonded to a backing plate composed of Cu using an In typebrazing material, whereby a several kinds of W sputtering targets wereobtained.

Crystal planes of the surface of the respective W sputtering targetswere analyzed by means of X-ray diffraction apparatus (XRD manufacturedby RIKEN), thereby to measure the half band width of a peakcorresponding to the crystal plane (110) and a dispersion of the halfband width. The measured results are shown in Table 1.

In table 1, the targets of No. 14-16 were subjected to a heat treatmentso that the W sintered body was heated to 1200° C. and held at thetemperature for 2 hours.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the following conditions:

-   Sputtering type: magnetron sputtering,-   Back pressure; 1×10⁻⁵ Pa,-   Output power DC; 2 kW,-   Ar; 0.5 Pa-   Sputtering time; 5 min,    thereby to form a W film on a 8-inch Si wafer. In order to measure a    uniformity in thickness of the W film, the film thickness was    measured with respect to points on a diameter line at interval of 5    mm from a peripheral portion of the Si wafer substrate. From a    maximum value and a minimum value of the measured thickness data,    the uniformity in thickness was calculated on the basis of the    following equation.    Uniformity in Film Thickness (%)={(maximum value−minimum    value)/(maximum value+minimum value)}×100

These results are shown in Table 1 in conjunction with the formerconditions. TABLE 1 Intermediate Sintering Step Dispersion of UniformityHeating Holding (110)Half in Film Speed Temp. Time (110)Half Band WidthThickness No. (° C./min) (° C.) (h) Finishing Work Band Width (%) (%)Examples 1 2 1400 1.5 Polishing with diamond abrasive grain 0.3288 28.10.98 2 3 1550 5 Polishing with G.C. grind stone 0.2998 25.2 0.94 3 21450 1.5 Polishing with diamond abrasive grain and Etching 0.1919 26.260.92 with red prussiate sol. for 1 min. 4 2.5 1450 2 Polishing withdiamond abrasive grain and Etching 0.1628 24.1 0.86 with red prussiatesol. for 3 min. 5 4 1550 5 Polishing with diamond abrasive grain andEtching 0.1331 20.5 0.75 with red prussiate sol. for 5 min. 6 4 1600 5Polishing with diamond abrasive grain and Etching 0.1006 14.3 0.68 withred prussiate sol. for 10 min. 7 3 1550 3 Polishing with G.C. grindstone and Etching with 0.1714 24.9 0.90 red prussiate sol. for 1 min. 84 1550 1.5 Polishing with G.C. grind stone and Etching with 0.1314 22.30.85 red prussiate sol. for 3 min. 9 3 1600 7 Polishing with G.C. grindstone and Etching with 0.1184 15.6 0.79 red prussiate sol. for 5 min. 105 1650 5 Polishing with G.C. grind stone and Etching with 0.0921 10.50.74 red prussiate sol. for 10 min. 11 2.5 1450 1.5 Polishing withdiamond abrasive grain and Dry 0.1442 28.8 0.88 Etching with CF₄/O₂mixed gas for 3 min. 12 3 1550 8 Polishing with diamond abrasive grainand Dry 0.1277 20.2 0.76 Etching with CF₄/O₂ mixed gas for 5 min. 13 41650 6 Polishing with diamond abrasive grain and Dry 0.0876 12.4 0.65Etching with CF₄/O₂ mixed gas for 10 min. 14 2.5 1450 2 Polishing withdiamond abrasive grain and 0.2212 21.2 0.89 Reverse-Sputter Etching withAr gas for 1 min. 15 3 1550 3 Polishing with diamond abrasive grain and0.1435 17.7 0.84 Reverse-Sputter Etching with Ar gas for 3 min. 16 3.51650 2 Polishing with diamond abrasive grain and 0.0957 14.3 0.71Reverse-Sputter Etching with Ar gas for 5 min. 17 10 1600 4 Polishingwith diamond abrasive grain and Etching 0.2882 45.6 1.58 with redprussiate sol. for 5 min. 18 10 800 8 Polishing with G.C. grind stoneand Etching with 0.3114 50.4 1.66 red prussiate sol. for 10 min.Comparative 19 20 900 0.5 None 0.4429 36.6 3.33 Examples 20 10 1000 0.1Lathe Work 0.5622 38.5 3.22 21 8 1900 2 Rotary grinding and Dry Etchingwith CF₄/O₂ 0.4233 37.9 3.66 mixed gas for 3 min 22 7 1000 0.2 Rotarygrinding and Dry Etching with CF₄/O₂ 0.4098 35.3 3.28 mixed gas for 5min 23 10 1500 0.5 Rotary grinding and Dry Etching with CF₄/O₂ 0.394231.5 3.24 mixed gas for 10 min 24 1 600 1.5 Rotary grinding and andReverse-Sputter Etching 0.4759 40.6 3.84 with Ar gas for 1 min. 25 301300 15 Rotary grinding and and Reverse-Sputter Etching 0.4422 36.8 3.41with Ar gas for 3 min. 26 7 1400 3 Rotary grinding and andReverse-Sputter Etching 0.4063 32.4 3.25 with Ar gas for 5 min. 27 31500 4 Rotary grinding and Dry Etching with CF₄/O₂ 0.4225 20.6 3.66mixed gas for 5 min 28 5 1600 10 Rotary grinding and and Reverse-SputterEtching 0.3988 22.3 3.34 with Ar gas for 1 min.

As is clear from the results shown in Table 1, the W sputtering targetsin which the half band width of a peak corresponding to the crystalplane (110) and a dispersion of the half band width of peak analyzed byX-ray diffraction of a surface to be sputtered are controlled to bewithin the range specified by this invention can provide an excellentuniformity in thickness of the W film in comparison with ComparativeExamples.

EXAMPLE 2

High purity W powders were prepared, and each of these high purity Wpowders was packed in a carbon mold die and the mold die was set into ahot pressing apparatus. Subsequently, an intermediate sintering wasperformed under the conditions shown in columns of the intermediatesintering step of Table 2. That is, each of the packed W powders washeated to the intermediate sintering temperature at heating speed shownin Table 2, and held at the temperature for the holding time shown inTable 2, thereby to perform the intermediate sintering step. After theabove intermediate sintering step, the sintered body was held at amaximum sintering temperature of 1900° C. for 5 hours while beingapplied with a pressure of 30 MPa under a vacuum atmosphere of 1 Pa orlower, thereby to prepare a W sintered body. Thereafter, this W sinteredbody was subjected to a HIP treatment such that the sintered body washeated to 1800° C. and held for 5 hours while being applied with apressure of 180 MPa, thereby to prepare a W sintered body as a targetmaterial.

Thus prepared W sintered body was then machine-worked so as to provide asize of the aimed target (diameter: 300 mm×thickness:5 mm). After thesurface of the target was subjected to a rotary grinding, a finishingwork shown in Table 2 was performed. Thus obtained sputtering target wasintegrally bonded to a backing plate composed of Cu using an In typebrazing material, whereby a several kinds of W sputtering targets wereobtained.

Under the same conditions as in Example 1, crystal planes of the surfaceof the respective W sputtering targets were analyzed by means of X-raydiffraction apparatus, thereby to measure the half band width of a peakcorresponding to the crystal plane (110) and a dispersion of the halfband width. The measured results are shown in Table 2.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the same conditions as in Example 1,thereby to form a W film on a 8-inch Si wafer. With respect to thusformed W film, a uniformity in thickness of the W film was measured.These results are shown in Table 2 in conjunction with the formerconditions. TABLE 2 Intermediate Sintering Step Dispersion of UniformityHeating Holding (110)Half (110)Half Band in Film Speed Temp. Time BandWidth Thickness No. (° C./min) (° C.) (h) Finishing Work Width (%) (%)Examples 29 3 1500 2 Polishing with diamond abrasive grain 0.2955 27.70.91 30 4 1450 5 Polishing with G.C. grind stone 0.2665 28.1 0.89 31 2.51600 3 Polishing with diamond abrasive grain and 0.1313 20.3 0.84Etching with red prussiate sol. for 3 min. 32 4.5 1400 6 Polishing withdiamond abrasive grain and 0.1111 11.3 0.51 Etching with red prussiatesol. for 20 min. 33 1 1400 5 Polishing with G.C. grind stone 0.2244 41.11.38 34 3 800 2 Polishing with diamond abrasive grain and 0.2386 46.91.56 Etching with red prussiate sol. for 20 min. Comparative 35 10 10000.5 None 0.4488 38.2 3.41 Examples 36 0.5 1400 7 Rotary grinding andEtching with red 0.3925 36.6 3.99 prussiate sol. for 3 min. 37 3 900 2Rotary grinding and Etching with red 0.3587 33.3 3.74 prussiate sol. for20 min. 38 2.5 1300 4 None 0.4266 20.6 4.21 39 4 1400 5 Rotary grindingand Etching with red 0.3993 22.4 4.35 prussiate sol. for 3 min.

As is clear from the results shown in Table 2, the W sputtering targetsin which the half band width of a peak corresponding to the crystalplane (110) and a dispersion of the half band width of peak analyzed byX-ray diffraction of a surface to be sputtered are controlled to bewithin the range specified by this invention can provide an excellentuniformity in thickness of the W film in comparison with ComparativeExamples.

EXAMPLE 3

High purity W powders were prepared, and each of these high purity Wpowders was subjected to a CIP treatment and followed by being subjectedto HIP treatment such that a molded body was heated to 1600° C. and heldfor 5 hours while being applied with a pressure of 150 MPa, thereby toobtain a W sintered body having a density of 96%. Thereafter, the Wsintered body was held in hydrogen gas atmosphere for 10 hours, andsubjected to a hot rolling under a temperature of 2200° C. in hydrogenatmosphere, thereby to obtain a W sintered body as a target material.

Thus obtained W sintered body was then machine-worked so as to provide asize of the aimed target (diameter: 300 mm×thickness:5 mm). After thesurface of the target was subjected to a rotary grinding, a finishingwork shown in Table 3 was performed. Thus obtained sputtering target wasintegrally bonded to a backing plate composed of Cu using an In typebrazing material, whereby a several kinds of W sputtering targets wereobtained.

Under the same conditions as in Example 1, crystal planes of the surfaceof the respective W sputtering targets were analyzed by means of X-raydiffraction apparatus, thereby to measure the half band width of a peakcorresponding to the crystal plane (110) and a dispersion of the halfband width. The measured results are shown in Table 3.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the same conditions as in Example 1,thereby to form a W film on a 8-inch Si wafer. With respect to thusformed W film, a uniformity in thickness of the W film was measured.These results are shown in Table 3 in conjunction with the conditions.TABLE 3 Dispersion of Uniformity in (110)Half (110)Half Band Width FilmThickness No. Finishing Work Band Width (%) (%) Examples 40 Polishingwith G.C. grind stone and Etching 0.2116 24.4 0.94 with red prussiatesol. for 3 min. 41 Polishing with G.C. grind stone and Etching 0.05779.3 0.62 with red prussiate sol. for 20 min. Comparative 42 None 0.453334.9 3.54 Examples 43 Lathe Work 0.5551 36.1 3.85 44 Lathe Work andEtching with red prussiate 0.5157 38.9 4.62 sol. For 3 min. 45 LatheWork and Etching with red prussiate 0.4889 33.1 4.03 sol. For 20 min.

As is clear from the results shown in Table 3, the W sputtering targetsin which the half band width of a peak corresponding to the crystalplane (110) and a dispersion of the half band width of peak analyzed byX-ray diffraction of a surface to be sputtered are controlled to bewithin the range specified by this invention can provide an excellentuniformity in thickness of the W film in comparison with ComparativeExamples.

EXAMPLE 4

CVD apparatus and material gas comprising WF₆ and H₂ were used forperforming a chemical deposition under a predetermined condition therebyto obtain a W sintered body.

Thus obtained W sintered body was then machine-worked so as to provide asize of the aimed target (diameter: 300 mm×thickness:5 mm). After thesurface of the target was subjected to a rotary grinding, a finishingwork shown in Table 4 was performed. Thus obtained sputtering target wasintegrally bonded to a backing plate composed of Cu using an In typebrazing material, whereby a several kinds of W sputtering targets wereobtained.

Under the same conditions as in Example 1, crystal planes of the surfacerespective W sputtering targets were analyzed by means of X-raydiffraction apparatus, thereby to measure the half band width of a peakcorresponding to the crystal plane (110) and a dispersion of the halfband width. The measure d results are shown in Table 4.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the same conditions as in Example 1,thereby to film on a 8-inch Si wafer. With respect to thus formed Wfilm, a uniformity in thickness of the W film was measured. Theseresults are shown in Table 4 conjunction with the conditions. TABLE 4Dispersion of Uniformity in (110)Half (110)Half Band Width FilmThickness No. Finishing Work Band Width (%) (%) Examples 46 Polishingwith diamond abrasive grain and 0.2998 25.2 0.93 Reverse-Sputter Etchingwith Ar gas for 3 min. 47 Polishing with diamond abrasive grain and0.1115 9.88 0.54 Reverse-Sputter Etching with Ar gas for 15 min.Comparative 48 None 0.4601 36.6 3.72 Examples 49 Lathe Work 0.5468 40.44.00 50 Lathe Work and Reverse-Sputter Etching with Ar 0.5233 38.8 3.86gas for 3 min. 51 Lathe Work and Reverse-Sputter Etching with Ar 0.500934.2 3.54 gas for 20 min.

As is clear from the results shown in Table 4, the W sputtering targetsin which the half band width of a peak corresponding to the crystalplane (110) and a dispersion of the half band width of peak analyzed byX-ray diffraction of a surface to be sputtered are controlled to bewithin the range specified by this invention can provide an excellentuniformity in thickness of the W film in comparison with ComparativeExamples.

Next, concrete examples of the present invention in which the crystalorientation ratio is specified will be explained hereunder.

EXAMPLE 5

High purity W powders were prepared, and each of these high purity Wpowders was packed in a carbon mold die and the mold die was set into ahot pressing apparatus. Then, each of the packed W powders was heated toa temperature shown in Table 5 and held for 3 hours under a vacuumatmosphere of 1 Pa or lower thereby to perform a degassing treatment.

Subsequently, each of the degassed molded bodies was repeatedlysubjected to a pressurization-depressurization cycle at a cycle numbershown in Table 5. The pressurization-depressurization cycle consists of:pressurizing the molded body to 30 MPa and depressurize it to normalpressure. Thereafter, an intermediate sintering was performed under theconditions shown in columns of the intermediate sintering step of Table5. That is, each of the degassed molded bodies was heated to theintermediate sintering temperature at heating speed shown in Table 5while being applied with a pressure of 30 MPa, and held at thetemperature for the holding time (2 hours) shown in Table 5, thereby toperform the intermediate sintering step.

After the above intermediate sintering step, the sintered body washeated to a temperature of 1900° C. and held for 5 hours, thereby toperform a final sintering. A cooling operation after the sintering wasperformed by substituting Ar gas for the atmosphere, and a cooling speedto a normal temperature was set to a value shown in Table 5, thereby toprepare a W sintered body as a target material. As shown in Table 5 assamples of 114-118, a part of the obtained sintered bodies weresubjected to a HIP treatment (180 MPa, 1800° C.), a hot forging at atemperature of 1600° C.(working ratio:20% and 15%) and a hydrogenannealing at a temperature of 1600° C.

With respect to each of thus obtained W sintered bodies prepared by therespective manufacturing methods, a machine-working was performed so asto provide a size of the aimed target (diameter: 300 mm×thickness:5 mm).After the surface of the target was subjected to a normal grinding suchas a rotary grinding, a finishing work, thus obtained each of thesputtering targets was integrally bonded to a backing plate composed ofCu using an In-type brazing material, whereby a several kinds of Wsputtering targets (samples 101-118) were obtained.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less. TABLE 5 Sintering Intermediate Degassing Cycle of SinteringFinal Sintering Cooling Pres- Holding Pressuri- Heating Tem- HoldingHolding Cooling Sam- sure Temp. Time Pressure zation Speed perature TimeTemp. Time Speed Post ple (Pa) Atmos. (° C.) (hr) (MPa) (Cycle) (°C./min) (° C.) (hr) (° C.) (hr) Atmos. (° C./min) Treatment 101 ≦1Vacuum 300 3 30 1 2 1650 2 1900 5 Ar 15 None 102 ≦1 Vacuum 600 3 30 2 21650 2 1900 5 Ar 15 None 103 ≦1 Vacuum 750 3 30 3 2 1650 2 1900 5 Ar 15None 104 ≦1 Vacuum 900 3 30 4 2 1650 2 1900 5 Ar 15 None 105 ≦1 Vacuum1000 3 30 4 2 1650 2 1900 5 Ar 15 None 106 ≦1 Vacuum 1200 3 30 5 2 16502 1900 5 Ar 15 None 107 ≦1 Vacuum 1300 3 30 5 2 1650 2 1900 5 Ar 15 None108 ≦1 Vacuum 1400 3 30 7 2 1650 2 1900 5 Ar 15 None 109 ≦1 Vacuum 15003 30 7 2 1650 2 1900 5 Ar 15 None 110 ≦1 Vacuum 1600 3 30 2 2 1650 21900 5 Ar 15 None 111 ≦1 Vacuum 1400 3 30 7 2 1600 2 1900 5 Ar 2 None112 ≦1 Vacuum 1400 3 30 7 2 1600 2 1900 5 Ar 12 None 113 ≦1 Vacuum 14003 30 7 2 1600 2 1900 5 Ar 20 None 114 ≦1 Vacuum 1400 3 30 7 2 1600 21900 5 Ar 5 HIP 115 ≦1 Vacuum 1400 3 30 7 2 1600 2 1900 5 Ar 20 HIP 116≦1 Vacuum 1400 3 30 7 2 1600 2 1900 5 Ar 15 Hot Forging (work ratio 20%)117 ≦1 Vacuum 1400 3 30 7 2 1600 2 1900 5 Ar 15 Hot Rolling (work ratio15%) 118 ≦1 Vacuum 1400 3 30 7 2 1600 2 1900 5 Ar 15 Hydrogen Annealing

The relative density of each of thus obtained W sputtering targets wasmeasured. The results are shown in Table 6.

Crystal planes of the surface of the respective W sputtering targetswere analyzed by means of X-ray diffraction apparatus (XRD manufacturedby RIKEN), thereby to measure the crystal orientation ratio (110)/(200)of peaks corresponding to the crystal planes (110), (200) and adispersion of the crystal orientation ratio. The measured results areshown in Table 6.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the following conditions i.e., sputteringtype: magnetron sputtering, back pressure; 1×10⁻⁵ Pa, output power DC; 2kW, Ar; 0.5 Pa, sputtering time; 5 min, thereby to form a W film on a8-inch Si wafer. In order to measure a uniformity in thickness of the Wfilm, the film thickness was measured with respect to points on adiameter line at interval of 5 mm from a peripheral portion of the Siwafer substrate. From a maximum value and a minimum value of themeasured thickness data, the uniformity in thickness was calculated onthe basis of the following equation.Uniformity in Film Thickness (%)={(maximum value−minimum value)/(maximumvalue+minimum value)}×100

These results are shown in Table 6 in conjunction with the other data.TABLE 6 Relative Crystal Dispersion of Crystal Uniformity DensityOrientation Orientation Ratio in Film Sample (%) Ratio (%) Thickness 10192.3 9.4 72.6 5.38 102 93.1 9.3 65.8 5.23 103 94.2 8.8 64.2 4.61 10496.1 8.5 58.9 3.88 105 97.6 8.2 59.2 2.92 106 99.1 6.1 8.9 0.88 107 99.23.2 8.7 0.83 108 99.2 0.5 6.9 0.84 109 97.5 0.04 35.6 2.80 110 94.5 0.0258.2 4.11 111 94.1 7.9 55.6 4.05 112 99.3 5.2 35.3 0.77 113 99.5 2.815.7 0.59 114 96.9 7.3 56.4 3.22 115 99.7 2.5 3.5 0.31 116 99.7 3.5 1.80.24 117 99.7 2.9 3.1 0.25 118 99.8 3.1 2.3 0.22

As clear from the results shown in Table 6, the W sputtering targets inwhich crystal orientation ratio (110)/(200) of peaks corresponding tothe crystal planes (110), (200) and a dispersion of the crystalorientation ratio analyzed by X-ray diffraction of a surface to besputtered are controlled to be within the range specified by thisinvention can provide an excellent uniformity in thickness of the W filmin comparison with Comparative Examples of which the crystal orientationratio is outside range of this invention.

EXAMPLE 6

High purity W powders were prepared, and each of these high purity Wpowders was pulverized by means of a ball mill under Ar atmosphere forthe pulverizing time shown in Table 7. Thus obtained each of thepulverized W powders was packed in a carbon mold die and the mold diewas set into a hot pressing apparatus. Then, each of the packed Wpowders was heated to a temperature shown in Table 7 and held for theholding time shown in Table 7 under a vacuum atmosphere of 1 Pa or lowerthereby to perform a degassing treatment.

Subsequently, each of the degassed molded bodies was applied with apressure of 10 MPa as a first pressurization and heated to anintermediate sintering temperature shown in Table 7 at a heating speedof 2 ° C./min, and held at the temperature for 2 hours, thereby toperform the intermediate sintering.

After the above intermediate sintering step, each of the sintered bodieswas once cooled to a cooling temperature shown in Table 7. Each of thecooled sintered bodies was applied with a pressure shown in Table 7 as asecond pressurization, and heated to a final sintering temperature shownin Table 7 at a heating speed of 2° C./min, and held at the finalsintering temperature for the holding time shown in Table 7, thereby toperform a final sintering. A cooling operation after the final sinteringwas performed by substituting Ar gas for the atmosphere, and a coolingspeed to a normal temperature was set to a value shown in Table 7,thereby to obtain respective W sintered bodies as target materials.

With respect to each of thus obtained W sintered bodies prepared by therespective manufacturing methods, a machine-working was performed so asto provide a size of the aimed target (diameter: 300 mm×thickness:5 mm).After the surface of the target was subjected to a normal grinding suchas a rotary grinding, a finishing work, thus obtained each of thesputtering targets was integrally bonded to a backing plate composed ofCu using an In-type brazing material, whereby a several kinds of Wsputtering targets (samples 119-137) were obtained.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less. TABLE 7 Sintering Intermediate Pulverizing Degassing 1^(st)Pressurization Sintering Pulverizing Hoding Heating Hoding Time PressureTemp. Time Pressure Speed Temp. Time Sample Atmos. (hr) (Pa) Atmos. (°C.) (hr) (MPa) (° C./min) (° C.) (hr) 119 None ≦1 Vacuum 1000 3 10 21650 2 120 None ≦1 Vacuum 1300 3 10 2 1650 2 121 Ar  5 ≦1 Vacuum 1300 310 2 1650 2 122 Ar 10 ≦1 Vacuum 1300 3 10 2 1650 2 123 Ar 15 ≦1 Vacuum1300 3 10 2 1650 2 124 Ar 24 ≦1 Vacuum 1300 3 10 2 1650 2 125 Ar 36 ≦1Vacuum 1300 3 10 2 1650 2 126 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2 127 Ar30 ≦1 Vacuum 1400 5 10 2 1600 2 128 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2129 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2 130 Ar 30 ≦1 Vacuum 1400 5 10 21600 2 131 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2 132 Ar 30 ≦1 Vacuum 1400 510 2 1600 2 133 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2 134 Ar 30 ≦1 Vacuum1400 5 10 2 1600 2 135 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2 136 Ar 30 ≦1Vacuum 1400 5 10 2 1600 2 137 Ar 30 ≦1 Vacuum 1400 5 10 2 1600 2Sintering 2^(nd) Pressurization Final Sintering Cooling Cooling HeatingHoding Cooling Temp. Pressure Speed Temp. Time Speed Sample (° C.) (MPa)(° C./min) (° C.) (hr) Atmos. (° C./min) 119 1200 None 1750 2 Ar 5 120900 50 2 1900 8 Ar 25 121 900 50 2 1900 8 Ar 25 122 900 50 2 1900 8 Ar25 123 900 50 2 1900 8 Ar 25 124 900 50 2 1900 8 Ar 25 125 900 50 2 19008 Ar 25 126 950 None 1900 10 Ar 30 127 950  5 2 1900 10 Ar 30 128 950 152 1900 10 Ar 30 129 950 30 2 1900 10 Ar 30 130 950 45 2 1900 10 Ar 30131 950 60 2 1900 10 Ar 30 132 950 50 2 1900 10 Ar 1 133 950 50 2 190010 Ar 2 134 950 50 2 1900 10 Ar 5 135 950 50 2 1900 10 Ar 8 136 950 50 21900 10 Ar 15 137 950 50 2 1900 10 Ar 30

The relative density of each of thus obtained W sputtering targets wasmeasured. The results are shown in Table 8.

Crystal planes of the surface of the respective W sputtering targetswere analyzed by means of X-ray diffraction apparatus (XRD manufacturedby RIKEN), thereby to measure the crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} of peaks corresponding to thecrystal planes (110), (200), (211), (220) and (310), and a dispersion ofthe crystal orientation ratio. The measured results are shown in Table8.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the following conditions i.e., sputteringtype: magnetron sputtering, back pressure; 1×10⁻⁵ Pa, output power DC; 2kW, Ar; 0.5 Pa, sputtering time; 5 min, thereby to form a W film on a8-inch Si wafer.

A number of particles each having a diameter of 1 μm or more that weremixed in the W film was measured by means of a particle counter (WN-3).The measured results was averaged from 300 sheets of the wafers. Theseresults are shown in Table 8 in conjunction with the other data. TABLE 8Relative Crystal Dispersion of Crystal Density Orientation OrientationRatio Particle Sample (%) Ratio (%) (pieces/wafer) 119 91.1 0.166 35.215.3 120 94.3 0.155 18.3 7.8 121 95.1 0.152 16.9 7.4 122 95.5 0.149 15.46.7 123 96.6 0.138 11.5 5.7 124 99.3 0.095 8.7 1.2 125 99.6 0.066 5.30.3 126 99.2 0.380 27.7 6.4 127 99.2 0.240 22.6 6.3 128 99.3 0.221 18.95.4 129 99.5 0.185 12.6 4.9 130 99.7 0.102 7.9 0.8 131 99.8 0.068 4.30.4 132 99.3 0.144 45.1 7.5 133 99.3 0.125 41.5 6.6 134 99.4 0.133 37.75.9 135 99.4 0.110 33.1 5.1 136 99.8 0.099 11.1 1.3 137 99.9 0.088 4.90.9

As is clear from the results shown in Table 8, the W sputtering targetsin which the crystal orientation ratio(211)/{(110)+(200)+(211)+(220)+(310)} of peaks corresponding to thecrystal planes (110), (200), (211), (220) and (310), and a dispersion ofthe crystal orientation ratio analyzed by X-ray diffraction of a surfaceto be sputtered are controlled to be within the range specified by thisinvention of provide an excellent characteristic in reducing thegeneration of the particles each having a diameter of 1 μm or more incomparison with Comparative examples of which the crystal orientationratio is outside range of this invention.

In the above Examples, although the case of the crystal orientationratio (110)/(200) of the crystal planes (110), (200) and the crystalorientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} are separatelyexplained, if the W sputtering target satisfies both of the abovecrystal orientation ratios, there can be obtained both an effect ofimproving the uniformity in film thickness and an effect of reducing theparticles.

As described above, according to the W sputtering targets of therespective Examples, it is possible to improve the in-plain uniformityin thickness of the W film formed on a large-sized substrate, and alsopossible to further reduce the generation of the particles.

EXAMPLE 7

High purity W powders were prepared, and each of these high purity Wpowders was pulverized by means of a ball mill under Ar atmosphere forthe pulverizing time shown in Table 9. Thus obtained each of thepulverized W powders was packed in a carbon mold die and the mold diewas set into a hot pressing apparatus. Then, each of the packed Wpowders was heated to a temperature shown in Table 9 and held for theholding time shown in Table 9 under a vacuum atmosphere of 1 Pa or lowerthereby to perform a degassing treatment.

Subsequently, each of the degassed molded bodies was repeatedlysubjected to a pressing/depressing cycle at a cycle number shown inTable 9. One cycle of the pressing/depressing cycle consists of:pressing the molded body to a pressure of 30 MPa; and depressing themolded body to a normal pressure. Thereafter, each of the degassedmolded bodies was applied with a pressure of 10 MPa as a firstpressurization and heated to an intermediate sintering temperature shownin Table 9 at a heating speed of 2° C./min, and held at the sinteringtemperature for 2 hours, thereby to perform the intermediate sintering.

After the above intermediate sintering step, each of the W sinteredbodies was once cooled to a cooling temperature shown in Table 9. Eachof the cooled W sintered bodies was applied with a pressure shown inTable 9 as a second pressurization, and heated to a final sinteringtemperature shown in Table 9 at a heating speed of 2° C./min, and heldat the final sintering temperature for the holding time shown in Table9, thereby to perform a final sintering. A cooling operation after thefinal sintering was performed by substituting Ar gas for the atmosphere,and a cooling speed to a normal temperature was set to a value shown inTable 9, thereby to obtain respective W sintered bodies as targetmaterials.

Thus obtained W sintered bodies manufactured through the respectivemethods were then machine-worked so as to provide a size of the aimedtarget (diameter: 300 mm×thickness:5 mm). After the surface of thetarget was subjected to a rotary grinding, a finishing work shown inTable 9 was performed. Thus obtained sputtering target was integrallybonded to a backing plate composed of Cu using an In type brazingmaterial, whereby a several kinds of W sputtering targets were obtained(as samples 201-210). TABLE 9 Sitering Pulverizing DegssingPressing/Depressing Cycle 1^(st) Pressurization Intermediate SinteringHolding Pres- Holding Cycle of Heating Holding Time sure Temp. TimePressure Pressurization Pressure Speed Temp. Time Sample Atmos. (hr)(Pa) Atmos. (° C.) (hr) (MPa) (Cycle) (MPa) (° C./min) (° C.) (hr) 201Ar 24 ≦1 Vacuum 1300  5 30 5 10 2 1600 2 202 Ar 24 ≦1 Vaccum 1400 10 307 10 2 1600 ″ 203 Ar 30 ≦1 Vacuum 1250 10 30 5 10 2 1650 ″ 204 Ar 30 ≦1Vacuum 1300 15 30 7 10 2 1700 ″ 205 Ar 30 ≦1 Vacuum 1400 20 30 10 10 21700 ″ 206 Ar 48 ≦1 Vacuum 1200 10 30 5 10 2 1600 ″ 207 Ar 48 ≦1 Vacuum1250 12 30 8 10 2 1650 ″ 208 Ar 48 ≦1 Vacuum 1350 15 30 10 10 2 1750 ″209 Ar 48 ≦1 Vacuum 1400 24 30 15 10 2 1750 ″ 210 Ar 60 ≦1 Vacuum 140036 30 8 10 2 1600 ″ Sitering 2^(nd) Pressurization Final SinteringCooling Cooling Heating Holding Cooling Temp. Pressure Speed Temp. TimeSpped Sample (° C.) (MPa) (° C./min) (° C.) (hr) Atmos. (° C./min)Finishing Work 201 800 40 2 1900 10 Ar 15 Polishing with diamondabrasive grain 202 850 50 2 1900 15 Ar 25 Polishing with diamondabrasive grain and Etching with red prussiate sol. for 3 min. 203 800 402 1900 10 Ar 15 Polishing with G.C. grind stone 204 850 45 2 1950 15 Ar25 Polishing with diamond abrasive grain and Etching with red prussiatesol. for 3 min. 205 900 60 2 1950 20 Ar 30 Polishing with diamondabrasive grain and Etching with red prussiate sol for 15 min. 206 800 402 1900 10 Ar 20 Polishing with diamond abrasive grain 207 850 50 2 190015 Ar 30 Polishing with G.C. grind stone 208 900 60 2 2000 20 Ar 30Polishing with diamond abrasive grain and Etching with red prussiatesol. for 3 min. 209 1000 60 2 2000 30 Ar 40 Polishing with diamondabrasive grain and Etching with red prussiate sol. for 20 min. 210 85040 2 1900 24 Ar 20 Polishing with diamond abrasive grain and Etchingwith red prussiate sol. for 30 min.

The relative density of each of thus obtained W sputtering targets wasmeasured.

Further, the crystal planes of the surface of the respective Wsputtering targets were analyzed by means of X-ray diffraction apparatus(XRD manufactured by RIKEN), thereby to measure the half band width of apeak corresponding to the crystal plane (110) and a dispersion of thecrystal orientation ratio. The measured results are shown in Table 10.

Further, the crystal orientation ratio {circumflex over (1)} (110)/(200)of peaks corresponding to the crystal planes (110), (200), and adispersion of the crystal orientation ratio were measured. The measuredresults are also shown in Table 10.

Furthermore, the crystal orientation ratio {circumflex over (2)}(211)/{(110)+(200)+(211)+(220)+(310)} of peaks corresponding to thecrystal planes (110), (200), (211), (220) and (310), and a dispersion ofthe crystal orientation ratio were measured. The measured results arealso shown in Table 10.

In this connection, an impurity content (a total amount of Fe, Ni, Cr,Cu, Al, Na, K, U and Th) contained in the respective targets was 10 ppmor less.

Using each of thus manufactured W sputtering targets, a sputteringoperation was performed under the following conditions i.e., sputteringtype: magnetron sputtering, back pressure; 1×10⁻⁵ Pa, output power DC; 2kW, Ar; 0.5 Pa, sputtering time; 5 min, thereby to form a W film on a8-inch Si wafer. In order to evaluate a uniformity in thickness of the Wfilm, the film thickness was measured with respect to measuring pointson a diameter line at interval of 5 mm from a peripheral portion of theSi wafer substrate. From a maximum value and a minimum value of themeasured thickness data, the uniformity in thickness was calculated onthe basis of the following equation.Uniformity in Film Thickness (%)={(maximum value−minimum value)/(maximumvalue+minimum value)}×100These results are shown in Table 10 in conjunction with the other data.

Further, a number of particles each having a diameter of 1 μm or morethat were mixed in the resultant W film was measured by means of aparticle counter (WN-3). The measured results was averaged from 300sheets of the wafers. These results are also shown in Table 10 inconjunction with the other data. TABLE 10 Crystal Orientation Ratio{circle over (1)}:(110)/(200) Crystal Orientation Ratio 2:(211)/[(110) +(200) + (211) + (220) + (310)} Dispersion of Dispersion of Dispersion ofUniformity in Relative (110)Half Band Crystal Crystal OrientationCrystal Crystal Orientation Film Particles Density (110)Half WidthOrientation Ratio {circle over (1)} Orientation Ratio {circle over (2)}Thickness (pieces/ Sample (%) Band Width (%) Ratio {circle over (1)} (%)Ratio {circle over (2)} (%) (%) wafer) 201 99.1 0.28 27.8 5.5 33.1 0.1515.4 0.88 1.8 202 99.5 0.19 20.1 2.1 10.7 0.08 7.8 0.54 0.8 203 99.30.31 14.3 6.1 45.9 0.16 25.6 0.92 1.5 204 99.5 0.22 18.6 3.4 31.1 0.1114.1 0.84 0.6 205 99.7 0.14 20.6 1.1 12.6 0.04 7.9 0.57 0.42 206 99.10.33 8.9 4.9 22.2 0.10 23.9 0.66 1.4 207 99.3 0.24 16.6 3.3 18.4 0.0610.3 0.41 0.8 208 99.9 0.11 28.1 4.2 9.8 0.05 6.5 0.32 0.4 209 99.9 0.052.9 0.9 5.5 0.02 4.1 0.66 0.2 210 99.8 0.09 5.4 1.9 11.9 0.08 6.7 0.380.8

As is clear from the results shown in Table 10, the W sputtering targetshaving a specified half band width of the crystal plane (110) of a peakanalyzed by X-ray diffraction of a surface to be sputtered, or the Wsputtering targets having a specified dispersion of the half band widthof the crystal plane (110), or the W sputtering targets having aspecified crystal orientation ratio (110)/(200), or the W sputteringtargets having a specified dispersion of the crystal orientation ratio(110)/(200), or the W sputtering targets in which the crystalorientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} of peakscorresponding to the crystal planes (110), (200), (211), (220) and(310), and a dispersion of the crystal orientation ratio analyzed byX-ray diffraction of a surface to be sputtered are controlled to bewithin the range specified by this invention are excellent in uniformityin film thickness and can provide an excellent characteristic inreducing the generation of the particles each having a diameter of 1 μmor more in comparison with Comparative Examples of which the crystalorientation ratio is outside range of this invention.

Industrial Applicability

As is clear from the above explanations, according to the high purity Wsputtering target of the present invention, it becomes possible toeffectively improve an in-plain uniformity in thickness of the W film.As a result, when the W film is used as electrodes or wirings or thelike of the semiconductor devices, a reliability of the semiconductordevice can be greatly improved, and a production yield of the devicescan be also improved.

Further, according to the method of manufacturing the high purity Wtarget of the present invention, it becomes possible to obtain a Wsputtering target capable of obtaining an excellent in-plain uniformityin thickness of the resultant W thin film.

1. A tungsten sputtering target in which a half band width of a peak corresponding to a crystal plane (110) of the target is 0.35 or less when a surface of the target to be sputtered is analyzed by X-ray diffraction.
 2. The tungsten sputtering target according to claim 1, wherein a dispersion of said half band width of said peak corresponding to the crystal plane (110) formed in the target surface is 30% or less.
 3. A tungsten sputtering target in which a crystal orientation ratio (110)/(200) is 0.1-6.5 when a peak intensity of a crystal plane (110) and a peak intensity of a crystal plane (200) of a surface of the target to be sputtered are analyzed by X-ray diffraction, and wherein a dispersion of said crystal orientation ratio (110)/(200) is 50% or less.
 4. (Deleted and incorporated into the original claim 2)
 5. A tungsten sputtering target in which a crystal orientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} is 0.17 or less when peak intensities of a crystal plane (110), a crystal plane (200), a crystal plane (211), a crystal plane (220) and a crystal plane (310) of a surface of the target to be sputtered are analyzed by X-ray diffraction, and wherein a dispersion of the crystal orientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} is 30% or less.
 6. (Deleted and incorporated into the original claim 5)
 7. A tungsten sputtering target in which a crystal orientation ratio (110)/(200) is 0.1-6.5 and a crystal orientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} is 0.17 or less when peak intensities of a crystal plane (110), a crystal plane (200), a crystal plane (211), a crystal plane (220) and a crystal plane (310) of a surface of the target to be sputtered are analyzed by X-ray diffraction, and wherein a dispersion of said crystal orientation ratio (110)/(200) is 50% or less and a dispersion of said crystal orientation ratio (211)/{(110)+(200)+(211)+(220)+(310)} is 30% or less.
 8. (Deleted and incorporated into the original claim 7)
 9. The tungsten sputtering target according to any one of claims 1 to 7, wherein said tungsten sputtering target has a relative density of 99% or more.
 10. The tungsten sputtering target according to any one of claims 1 to 9, wherein said tungsten sputtering target is used for forming an electrode and/or wiring of a semiconductor element.
 11. The tungsten sputtering target according to any one of claims 1 to 10, wherein said tungsten sputtering target is integrally bonded to a backing plate.
 12. The tungsten sputtering target according to any one of claims 1 to 11, wherein said tungsten sputtering target is subjected to a grinding work of at least one of rotary grinding and polishing, and further subjected to a finishing work of at least one of etching and reverse sputtering.
 13. The tungsten sputtering target according to claim 11, wherein said tungsten sputtering target is integrally bonded to a backing plate by means of diffusion bonding or brazing.
 14. The tungsten sputtering target according to any one of claims 1 to 9, wherein a total amount of iron, nickel, chromium, copper, aluminum, sodium, potassium, uranium and thorium as impurities contained in said tungsten sputtering target is 100 ppm or less.
 15. A method of manufacturing the tungsten sputtering target according to any one of claims 1 to 14, the method comprising the steps of: pressing a high purity tungsten powder to form a pressed compact; sintering the pressed compact to form a sintered body; working the sintered body to obtain a shape of a target; subjecting the target to a grinding work of at least one of rotary grinding and polishing; and subjecting the target to a finishing work of at least one of etching and reverse sputtering.
 16. The method of manufacturing the tungsten sputtering target according to claim 14, further comprising an intermediate sintering step for maintaining the pressed compact at temperature of 1450-1700° C. for one hour or longer after the pressed compact is heated at a heating-up rate of 2-5° C./min on the way to a maximum sintering temperature when the high purity tungsten powder is pressed and sintered by hot pressing method. 